BOSTON — As hard as he tried, Jarrod Parker couldn’t quite stop a grin from coming to his face in Oakland’s locker room.

He was entitled to a little emotion after keeping his composure while shutting down Boston’s resurgent offense and picking up his first major league win when the Oakland Athletics beat the Red Sox 5-3 on Tuesday night.

“It’s pretty cool,” Parker said between grins. “I don’t think it will set in until maybe tomorrow or when I’m fielding phone calls later tonight.”

The 23-year-old right-hander scattered four hits over 6 2-3 innings, holding Boston to just a run one night after the Red Sox racked up 11 runs on 11 hits off Oakland pitchers.

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The few times Parker got in trouble, he quickly got himself out of the threat before it could get worse as the A’s evened the three-game series 1-all on a frigid night at Fenway Park.

“As long as he throws the ball over the plate with his stuff, he’s going to have some success,” Oakland manager Bob Melvin said. “I don’t want to say you worry, but you really want to see how a young pitcher like that handles his first time at Fenway Park and he handled it beautifully.”

Jemile Weeks ended on 0-for-12 slump with a leadoff single and finished 2-for-5 with two RBIs and two runs scored for the A’s, who ended a three-game losing streak.

Oakland scored the first five runs and provided plenty of security for Parker (1-0), who was making just his third start in the majors.

Parker was recalled from Triple-A Sacramento last Wednesday and got a no-decision against Chicago that night. Parker struck out four, walked two and hit a batter before getting pulled in the seventh inning.

Parker said he just followed catcher Kurt Suzuki’s lead and didn’t try anything fancy.

“I don’t think we threw more than five or six breaking balls. Just going at guys moving the ball in and out was effective tonight,” Parker said.

Boston starter Felix Doubront (1-1) wasn’t nearly as effective. The left-hander threw 30 pitches in the first inning alone and struggled through four innings. He struck out eight, but also allowed six hits, walked two and threw two wild pitches while allowing five runs.

“He’s been the master of the one-ball, two-strike count and tonight he was behind virtually ever hitter,” Boston manager Bobby Valentine said.

The Red Sox had just four hits until Cody Ross led off the ninth with a double to left off of Grant Balfour. Marlon Byrd singled with one out, Punto walked to load the bases for Mike Aviles, who lined a single to center and cut Oakland’s lead to 5-3.

“We’re down 5-1. It’s very easy to fold, get three quick outs and take it to the house,” Aviles said. “It’s cold weather, nasty weather, but I think it just shows a lot about the team. We came back and we tried to give it a little fight.”

Jordan Norberto came in for Oakland and got the save, striking out Lars Anderson and getting Dustin Pedroia to ground out to second. It was Norberto’s first save in the majors, leaving the A’s in a bit of a quandary deciding whether the reliever or starter would get the game ball.

“I don’t know who has the ball,” Parker said. “We might have to cut it in half.”

David Ortiz, who was hitting .543 at home, went 0-for-4 and saw his average drop from .405 to .386.

Pedroia was the only player to score on Parker. He led off the fourth with a single, advanced to second on a wild pitch and came home on back-to-back fielder’s choices to cut Oakland’s lead to 5-1.

Parker started to struggle in the seventh when Ross led off with a double down the left field line and Punto drew a two-out walk. Parker was pulled for reliever Brian Fuentes, who got out of the jam on a nice defensive play by third baseman Brandon Inge, picked up by Oakland on Monday. Mike Aviles hit a sharp grounder, which Inge lunged to get then scrambled to his feet in time to dive in front of the bag and tag out Ross.

“He does that all the time. When you’re around him you see him a lot, he kind of spoils you with things like that,” Melvin said. “Certainly at that point in time of the game it was big.”

The A’s got to Doubront for four runs in the fourth. Suzuki singled with one out, Kila Ka’aihue walked and Cliff Pennington drove in Suzuki with a double. Weeks followed with a long single that scored Ka’aihue and Pennington. Weeks took second when the throw to the plate wasn’t in time to catch Pennington, stole third and trotted home on a wild pitch to put the A’s up 5-0.

Oakland stole third base four times.

Notes: A cold, steady rain fell throughout the day in Boston and the Fenway Park organist was playing “Let the Sun Shine” about an hour before gametime as the rain continued to fall on the tarp covering the infield. … Because of the rain, neither team took batting practice. … Melvin said he thought Weeks’ offensive struggles may have contributed to his defensive play, including a costly error in Boston’s 11-6 win Monday night. “When you’re not playing and swinging the bat to your ability sometimes you go out there and that frustration just comes out there with you in the field.” … Melvin put Ka’aihue at first base so he could face the left-handed Doubront. … Boston recalled SS Jose Iglesias and sent RHP Junichi Tazawa to Triple-A Pawtucket earlier Tuesday. … 3B Kevin Youkilis was scratched from the lineup for the third straight game with stiffness in his back.